A Denver grand jury report [PDF] released Thursday concludes that the Jefferson County sheriff's office may have purposely destroyed documents regarding the investigation into the Columbine High School shootings. The report's criticism focuses in large part on John Kiekbusch, a former administrator in the sheriff's office, but the grand jury said that it did not have enough evidence to indict anyone because all witnesses disavowed any knowledge or involvement into the disappearance of the files. The report notes that Kiekbusch ended a 1999 effort to find the files and asked an assistant to shred a large pile of copies of Columbine related reports in 2000.

The search for the missing files center on a draft affidavit for a warrant to search Eric Harris' home a year before the Columbine shootings, which the sheriff's office prepared after being tipped that Harris built pipe bombs and made violent Internet postings. High-ranking Jefferson County officials and law enforcement agreed not to disclose the existence of the affidavit, but its existence was brought to light in 2001 when a judge ordered its release.

The Rocky Mountain News and AP have more. Read the grand jury's supplementary report here [PDF], or visit the Rocky Mountain News' special Columbine section for further information.